syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P19088
rcu: 	(detected by 1, t=10502 jiffies, g=96277, q=786 ncpus=2)
task:syz.2.4448      state:R  running task     stack:26312 pid:19088 ppid:12333  flags:0x0000400e
Call Trace:
 <IRQ>
 sched_show_task+0x49b/0x5c0 kernel/sched/core.c:9179
 rcu_print_detail_task_stall_rnp kernel/rcu/tree_stall.h:261 [inline]
 print_other_cpu_stall+0xff9/0x1380 kernel/rcu/tree_stall.h:637
 check_cpu_stall kernel/rcu/tree_stall.h:809 [inline]
 rcu_pending kernel/rcu/tree.c:3950 [inline]
 rcu_sched_clock_irq+0x88e/0x1230 kernel/rcu/tree.c:2295
 update_process_times+0x147/0x1b0 kernel/time/timer.c:2072
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x3a2/0x580 kernel/time/tick-sched.c:1492
 __run_hrtimer kernel/time/hrtimer.c:1754 [inline]
 __hrtimer_run_queues+0x4e1/0xc40 kernel/time/hrtimer.c:1818
 hrtimer_interrupt+0x3c9/0x9c0 kernel/time/hrtimer.c:1880
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline]
 __sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0x51/0xc0 arch/x86/kernel/apic/apic.c:1088
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:stack_trace_consume_entry+0x126/0x270 kernel/stacktrace.c:94
Code: 89 d4 4c 89 c5 e8 2a a3 69 00 49 89 e8 4c 89 e2 48 89 de 49 89 37 41 8b 18 41 0f b6 44 15 00 84 c0 0f 85 2f 01 00 00 41 3b 1e <0f> 92 c0 48 83 c4 18 5b 41 5c 41 5d 41 5e 41 5f 5d c3 44 89 c1 80
RSP: 0018:ffffc900001eef78 EFLAGS: 00000283
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffff88804f36bc00
RDX: dffffc0000000000 RSI: ffffffff81df3fae RDI: ffffc900001ef080
RBP: 1ffff9200003de12 R08: ffffc900001ef090 R09: 0000000000000000
R10: 0000000000000004 R11: 0000000000000100 R12: 0000000000000000
R13: 1ffff9200003de11 R14: ffffc900001ef088 R15: ffffc900001ef100
 arch_stack_walk+0x138/0x190 arch/x86/kernel/stacktrace.c:27
 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522
 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237
 kasan_slab_free include/linux/kasan.h:164 [inline]
 slab_free_hook mm/slub.c:1811 [inline]
 slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837
 slab_free mm/slub.c:3830 [inline]
 kmem_cache_free+0xf8/0x270 mm/slub.c:3852
 dev_kfree_skb_any_reason+0x120/0x130 net/core/dev.c:3241
 free_old_xmit_skbs+0x11a/0x3d0 drivers/net/virtio_net.c:780
 start_xmit+0x168/0x14a0 drivers/net/virtio_net.c:2420
 __netdev_start_xmit include/linux/netdevice.h:4943 [inline]
 netdev_start_xmit include/linux/netdevice.h:4957 [inline]
 xmit_one net/core/dev.c:3644 [inline]
 dev_hard_start_xmit+0x246/0x740 net/core/dev.c:3660
 sch_direct_xmit+0x25e/0x4c0 net/sched/sch_generic.c:345
 __dev_xmit_skb net/core/dev.c:3881 [inline]
 __dev_queue_xmit+0x165d/0x3660 net/core/dev.c:4416
 neigh_output include/net/neighbour.h:543 [inline]
 ip_finish_output2+0xd3a/0x11e0 net/ipv4/ip_output.c:235
 NF_HOOK_COND include/linux/netfilter.h:293 [inline]
 ip_output+0x2a1/0x3b0 net/ipv4/ip_output.c:436
 dst_output include/net/dst.h:467 [inline]
 ip_local_out net/ipv4/ip_output.c:129 [inline]
 __ip_queue_xmit+0x1049/0x1950 net/ipv4/ip_output.c:540
 __tcp_transmit_skb+0x1d6d/0x33f0 net/ipv4/tcp_output.c:1427
 tcp_ack_snd_check net/ipv4/tcp_input.c:5738 [inline]
 tcp_rcv_established+0xb06/0x1d20 net/ipv4/tcp_input.c:6184
 tcp_v4_do_rcv+0x4ed/0xb80 net/ipv4/tcp_ipv4.c:1735
 tcp_v4_rcv+0x23bf/0x2af0 net/ipv4/tcp_ipv4.c:2167
 ip_protocol_deliver_rcu+0x20e/0x3f0 net/ipv4/ip_input.c:205
 ip_local_deliver_finish+0x2ca/0x510 net/ipv4/ip_input.c:233
 NF_HOOK+0x32d/0x3b0 include/linux/netfilter.h:304
 dst_input include/net/dst.h:477 [inline]
 ip_sublist_rcv_finish net/ipv4/ip_input.c:580 [inline]
 ip_list_rcv_finish net/ipv4/ip_input.c:631 [inline]
 ip_sublist_rcv+0xa4c/0xd70 net/ipv4/ip_input.c:639
 ip_list_rcv+0x3f2/0x440 net/ipv4/ip_input.c:674
 __netif_receive_skb_list_ptype net/core/dev.c:5689 [inline]
 __netif_receive_skb_list_core+0x583/0x750 net/core/dev.c:5737
 __netif_receive_skb_list net/core/dev.c:5789 [inline]
 netif_receive_skb_list_internal+0x943/0xca0 net/core/dev.c:5880
 gro_normal_list include/net/gro.h:451 [inline]
 gro_normal_one include/net/gro.h:464 [inline]
 napi_skb_finish net/core/gro.c:577 [inline]
 napi_gro_receive+0x565/0xb00 net/core/gro.c:607
 receive_buf+0x2203/0x3820 drivers/net/virtio_net.c:1870
 virtnet_receive drivers/net/virtio_net.c:2155 [inline]
 virtnet_poll+0x5dd/0x1280 drivers/net/virtio_net.c:2229
 __napi_poll+0xc0/0x460 net/core/dev.c:6650
 napi_poll net/core/dev.c:6717 [inline]
 net_rx_action+0x616/0xc40 net/core/dev.c:6853
 handle_softirqs+0x280/0x820 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0xd3/0x190 kernel/softirq.c:661
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:finish_task_switch+0x26a/0x8f0 kernel/sched/core.c:5255
Code: 0f 84 33 01 00 00 48 85 db 0f 85 52 01 00 00 0f 1f 44 00 00 4c 8b 75 d0 4c 89 e7 e8 20 84 33 09 e8 3b 2e 30 00 fb 4c 8b 65 c0 <49> 8d bc 24 f8 15 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0
RSP: 0018:ffffc900032e75b8 EFLAGS: 00000286
RAX: 01adf580f8298500 RBX: 0000000000000000 RCX: 01adf580f8298500
RDX: dffffc0000000000 RSI: ffffffff8acacbe0 RDI: ffffffff8b1c9a20
RBP: ffffc900032e7610 R08: ffffffff8e8b3aef R09: 1ffffffff1d1675d
R10: dffffc0000000000 R11: fffffbfff1d1675e R12: ffff88804f36bc00
R13: dffffc0000000000 R14: ffff88801a27bc00 R15: ffff8880b8f3cac8
 context_switch kernel/sched/core.c:5384 [inline]
 __schedule+0x155b/0x45a0 kernel/sched/core.c:6700
 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7010
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:trace_lock_acquire include/trace/events/lock.h:24 [inline]
RIP: 0010:lock_acquire+0xbf/0x420 kernel/locking/lockdep.c:5725
Code: 7e 83 f8 08 0f 83 a0 01 00 00 41 89 c6 c1 e8 06 48 8d 3c c5 e8 3a 8b 8e be 08 00 00 00 e8 69 3c 77 00 4c 0f a3 35 49 0a 23 0d <73> 0d e8 9a b9 08 00 84 c0 0f 84 2e 02 00 00 48 c7 c0 9c 6f 8b 8e
RSP: 0018:ffffc900032e79a0 EFLAGS: 00000257
RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff81683097
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e8b3ae8
RBP: ffffc900032e7aa8 R08: ffffffff8e8b3aef R09: 1ffffffff1d1675d
R10: dffffc0000000000 R11: fffffbfff1d1675e R12: 1ffff9200065cf40
R13: ffffffff8d132120 R14: 0000000000000000 R15: dffffc0000000000
 rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 rcu_read_lock include/linux/rcupdate.h:786 [inline]
 sched_mm_cid_remote_clear_old kernel/sched/core.c:11936 [inline]
 task_mm_cid_work+0x33a/0x770 kernel/sched/core.c:11997
 task_work_run+0x1d4/0x260 kernel/task_work.c:245
 get_signal+0x1235/0x13f0 kernel/signal.c:2678
 arch_do_signal_or_restart+0xc2/0x800 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fb52c39ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb52d2d7028 EFLAGS: 00000246 ORIG_RAX: 000000000000012a
RAX: 0000000000000007 RBX: 00007fb52c615fa0 RCX: 00007fb52c39ce59
RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 00002000000008c0
RBP: 00007fb52c432d6f R08: 0000000000000002 R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb52c616038 R14: 00007fb52c615fa0 R15: 00007ffe047df4e8
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 451 jiffies! g96277 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=61475
rcu: rcu_preempt kthread starved for 452 jiffies! g96277 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:I stack:25912 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5381 [inline]
 __schedule+0x1553/0x45a0 kernel/sched/core.c:6700
 schedule+0xbd/0x170 kernel/sched/core.c:6774
 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x313/0x1590 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5755 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:pv_native_safe_halt+0xf/0x10 arch/x86/kernel/paravirt.c:148
Code: 68 20 02 c3 cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d 43 f4 40 00 fb f4 <c3> 66 0f 1f 00 55 41 57 41 56 41 54 53 50 8b 2f eb 2e 41 89 de 80
RSP: 0018:ffffc9000458f6d8 EFLAGS: 000002d3
RAX: ffffffff813aa578 RBX: 0000000000000003 RCX: ffff8880222b5a00
RDX: 0000000000000000 RSI: ffffffff8acacbe0 RDI: ffffffff8b1c9a20
RBP: ffffc9000458f7b0 R08: ffffffff911c95c7 R09: 1ffffffff22392b8
R10: dffffc0000000000 R11: fffffbfff22392b9 R12: dffffc0000000000
R13: 0000000000000200 R14: 0000000000000003 R15: 1ffff920008b1ee0
FS:  0000555582aaa500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f93edc00000 CR3: 000000007e5d8000 CR4: 00000000003506f0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline]
 kvm_wait+0x23d/0x2a0 arch/x86/kernel/kvm.c:1058
 pv_wait arch/x86/include/asm/paravirt.h:598 [inline]
 pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline]
 __pv_queued_spin_lock_slowpath+0x61a/0x9d0 kernel/locking/qspinlock.c:511
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:586 [inline]
 queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline]
 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
 do_raw_spin_lock+0x23e/0x2c0 kernel/locking/spinlock_debug.c:115
 spin_lock_bh include/linux/spinlock.h:356 [inline]
 lock_sock_nested+0x6a/0x100 net/core/sock.c:3538
 lock_sock include/net/sock.h:1780 [inline]
 tcp_recvmsg+0x214/0x860 net/ipv4/tcp.c:2607
 inet_recvmsg+0x140/0x1f0 net/ipv4/af_inet.c:882
 sock_recvmsg_nosec net/socket.c:1046 [inline]
 sock_recvmsg net/socket.c:1068 [inline]
 sock_read_iter+0x2d9/0x3e0 net/socket.c:1138
 call_read_iter include/linux/fs.h:2012 [inline]
 new_sync_read fs/read_write.c:389 [inline]
 vfs_read+0x46a/0x970 fs/read_write.c:470
 ksys_read+0x150/0x260 fs/read_write.c:613
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f93eff57fd7
Code: 48 89 fa 4c 89 df e8 a8 56 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffc12b562d0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000555582aaa500 RCX: 00007f93eff57fd7
RDX: 0000000000000004 RSI: 00007ffc12b5632c RDI: 0000000000000003
RBP: 00007ffc12b567d0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000004
R13: 00007ffc12b5632c R14: 00007ffc12b563c0 R15: 0000000000000000
 </TASK>